AMD Ryzen Threadripper 1950X Review

Overclocking, Cooling & Temperature

The Right Cooling Solution

AMD doesn't use thermal paste between the Ryzen Threadripper processors’ dies and integrated heat spreader. Instead, it went with good old solder. This decision should prove critical during our overclocking efforts.

Most reviewers (us included) received all-in-one liquid coolers for their Threadripper CPUs. They're made by Thermaltake and include a flat 360mm radiator with three 120mm fans.

Fully assembled, and sitting next to the motherboard and RGB-lit memory sticks, the whole kit lights up like a Christmas tree. At least it was (almost) fully functional. The only exception was the original thermal paste on Asetek's pump. There was simply not enough of it. Even without overclocking, AMD’s new processor can hit 180W under heavy load, and its heat spreader is relatively large. This combination requires a different approach. Instead of the usual centered blob, we drew a thick line with the thermal paste. We then put the pump in place and gently rotated it back and forth while manually applying some pressure. Only then did we screw it in place.

Installing Your Own Water Cooler

We’ve already reported how AMD changed its interface for Socket TR4 (SP3r2). One of the most important alterations involves the screws. AMD went with M3.5 screws, an uncommon size with a fine thread. You won’t find these at your local hardware store. The difference can easily be spotted in the picture below, with our purchase on the left and an original AM4 screw on the right:

Simply shipping brackets of a different size won’t do the trick here. The acquisition of suitable screws is also necessary. The socket’s threads don’t go all the way through, which is to say that they aren’t open in the back. So, the screws also need to be of the correct length. We tried 20mm screws, and they turned out to be too long. Then we experimented with fitting spacers. A good length for the screws would have been 15mm, but this might vary depending on the bracket’s thickness.

The next question, which is even more important than the first one, is how much pressure to apply. We used a special torque wrench with very small steps and M3.5 screws with internal hexagonal threads, and started with a reasonable 0.1Nm. From approximately 0.25Nm, we couldn’t detect any further gains in cooling performance, so that's where we stopped. A sensible maximum pressure is approximately 0.35Nm.

The picture below shows our completely installed cooling solution. The CPU block’s an Alphacool XPX with a bracket for AMD’s Socket TR4 (SP3r2). The polyamide washers are used as spacers and take the place of springs. The top washers are made of steel to keep the head of the cylinder from boring into the much softer washer material during the CPU block’s installation.

Overclocking

Our Ryzen Threadripper 1950X sample overclocked to 3.9 GHz and 1.35V. However, the all-in-one water cooling solution in our kit couldn’t keep the system stable at that level. This was due to the processors’ power consumption rising to more than 250W during rendering.

And so we went back to our Chiller to achieve some better comparisons. This way, there’s one true constant to our measurements: a water temperature of approximately 20°C, which can be held constant, even topping more than 300W of waste heat.

For everyday use, a normal water-cooling solution will definitely suffice thanks to the soldered heat spreader, which makes AMD’s processor much less of a challenge than Intel's Core i9-7900X. Our approach simply allows us a bit more sophistication in our overclocking endeavors.

Using the Chiller, AMD’s Ryzen Threadripper 1950X achieved 4 GHz at 1.45V. Just don't expect to see those results from your own overclock. Even the Chiller started to fall behind the CPU's thermal output as temperatures crept too high for comfort. This is why the processor is overclocked to more reasonable levels for our benchmarks, with Threadripper running at 3.9 GHz.

Maximum Temperatures: Stock Clock Rate

AMD circulated a 27°C addition to the Tctl values, which is supposed to amount to the average core temperature. This sounds about right to us after taking a look at the temperature difference between Tctl and Tdie (the latter being the chip temperature). Between this and the fact that a huge cooler made it practically impossible to conduct our own heat spreader measurements, we're forgoing the delta measurements you saw in our Ryzen 3, 5, and 7 reviews.

We stick with the water cooling solution that AMD provided for our first results. As a bit of a power consumption spoiler, the motherboard limits the two CPUs between 179 and 180W. This upper boundary can’t even be exceeded for short periods of time using normal motherboard settings.

Here are the temperature curves:

The CPU temperature values reported by HWInfo64 through Asus' separate sensor loop are between 6°C and 12°C lower than the Tctl values, and they rise more slowly. The voltage converter temperatures of just under 60°C, achieved without any additional cooling, are great.

Maximum Temperatures: Overclocked

Increasing voltages to guarantee stable operation pushes the processor well beyond its sweet spot. Consequently, power consumption goes through the roof. Operating well beyond 300W poses a challenge for any cooling solution. That's why we're using the Chiller. We did try a normal water-cooling loop though, resulting in the Tctl and Tdie values going up by ~10°C to 15°C. This is well within an acceptable range.

The overclocked 1950X peaks at a hefty 320 to 325W. Using the Chiller, this level of power consumption is accompanied by Tctl values of 87°C. That’s actually not as severe as it seems once the offset and Tdie values are taken into account. A real temperature of approximately 60°C serves as a great demonstration of why solder is superior to thermal paste. Intel's Core i9-7900X could have had so much potential if the company hadn't taken the easy way out.

Voltage Converter Temperatures

We’ll conduct a separate test with different loads and X399 motherboards in the future. As for the Asus X399 ROG Zenith, its voltage converters generally stay under 100°C without any additional air cooling, even as AMD's CPU consumes well over 300W.

Asus set its throttling temperature threshold to 105°C. Even a bit of airflow helps, though. This is demonstrated quite nicely by the temperature curves for the overclocked configuration above. The fan that’s installed right above the I/O shield doesn’t really have any effect, unless you count its unnecessarily high noise level. Asus should have done without this gimmick.

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  • vMax
    Very good in depth review. Threadripper looks like a great productivity CPU especially for the price to performance... At last AMD are back at the big table and thats not to put Intel down as they still make the fastest CPU's overall...just you have pay that much more for the privilege, but finaly we have a real choice at all price points... Great for the consumer. Good job Tom's and AMD.
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  • HEXiT
    so happy this has happend. intel wont be, but for amd, its great news. 95%+ the perfomance for half the price makes threadripper a very attractive cpu for virtual machines and even office environments that use terminals rather than every 1 using a desktop.
    so much potential for a £2k build that just wasnt there a year ago...
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  • fla56
    where is XFR testing?

    surely it's clear by now that the worst way to overclock a Ryzen is to try and overclock the cores?
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  • gferrin2012
    Hmm. I will first state I have no preference to AMD nor Intel. I can buy any CPU, or GPU that suits my needs. I looked over you "benches" and I will be very upfront. I do not believe yours. I think the "threadripper" benches a lot better than your are showing. Your test methods seem to favor Intel. I have long suspected and heard of Toms Hardware of being an Intel fanboy site. I have owned Intel and swore by them for years. In am considering AMD for the first time. I will continue to look at, what I believe, to be more honest test sites. Lets see how this plays out. I happen to have a friend who has an 1800x and and another associate that has an I7-7700k. I am familiar with Blenders Bmw benchmark. I would like an explanation as to why, in CPU rendering using blender 2.78c, the 1800x literally destroys the I7-7700k.
    If you look at my account (go ahead) here on Toms Hardware, you will notice I am not an AMD fanboy at all. When I start feeling I am getting biased reviews and have the sneaking suspicion of Intel slipping the 'ol kickback to you, it's time to delete my membership.
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  • HEXiT
    i think the variance between these and other benches is the way they have done em... maybe they didnt set the cpu to productivity and just used gaming mode or vies-versa. but there is some discrepancy between what im seeing here and elsewhere. whats up toms. normally your stuff is accurate.
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